Abstract: The present invention provides a connecting device which has a connecting portion capable of rotatably connecting two housing portions without protruding from the two housing portions and can stably keep the housing portions arranged so as to face each other. The connecting device includes; first and third connecting members 31 and 33 which have flexibility and foldably connect an upper housing portion 1 and a lower housing portion 2 with a predetermined gap interposed therebetween; and a second connecting member 32 which has enough restoring force and rigidity to restore a bent state to an unbent state and is curved in an arc shape in sectional view such that a concave portion of the arc is oriented in a direction where the upper and lower housing portions are folded.